PROJECT SUMMARY/ABSTRACT Bipolar disorder and schizophrenia, both serious mental illnesses (SMIs), are present in up to one third of suicide deaths, and yet research is lacking on suicide-specific interventions in this large population. Walk-in urgent care clinics are a best practice in increasing access to mental health care for SMI, and many people with SMI who present to such clinics are at elevated risk for suicide. Yet, only 50% of patients who are referred from urgent care do not attend follow up outpatient appointments. Thus, walk-in clinics provide an important and novel setting in which to deploy suicide-specific interventions that bridge the transition from urgent to outpatient care. This intervention development research project evaluates the feasibility, acceptability, and preliminary impact of a brief cognitive behavioral intervention, tailored to SMI, that is delivered during the gap period between urgent care evaluation and follow-up outpatient care. SafeTy and Recovery Therapy (START) is a 4-session cognitive behavioral intervention augmented by mobile technology, which delivers automated and personalized reinforcement of adaptive coping behavior outside of the clinic setting. START builds from collaborative development alongside a community psychiatric service organization, and our preliminary data in the SMI population that supports the feasibility, acceptability, and impact of brief, mobile augmented cognitive behavioral intervention. Preliminary data also support the impact of mobile augmented CBT in enhancing treatment adherence and coping self-efficacy, along with providing novel insights on the near term dynamics of suicide-related exacerbations through intensive longitudinal data. In a 3- year developmental study, our deployment focused approach will first refine intervention procedures, safety and care continuity protocols, and fit with the deployment setting with a series of collaborative contacts with community providers, project staff, advisors, and patient advocates. We will next conduct a pilot randomized controlled trial with 70 patients diagnosed with either bipolar disorder or schizophrenia rapidly referred by community triage providers to receive START in the walk-in clinic setting. Patients are enrolled who have SMI diagnoses and current active suicidal ideation and/or a suicide attempt in the prior 3 months. Participants are randomized to one of two active conditions: START + Mobile augmentation or START alone. We will evaluate feasibility, acceptability, and enhancement of rates of outpatient treatment engagement and crisis service use in comparison to the sample population. We will also examine pragmatic mechanisms, which include outpatient treatment engagement and coping self-efficacy, on change in suicidal ideation severity and crisis service use along with the preliminary impact of mobile augmentation. Subsequent to this developmental research, the intervention developed here could be readily scaled to the wider network of walk-in clinics serving people with SMI in effort to reduce the high rate of suicide in this vulnerable population.